Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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How does a recipient share his/her address with a Sender?

Person A wants to send some Bitcoins to person B. How will person A come to know about the person B's address? And for every transaction Person B's address (as well as Person A's) changes. How will ...
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2answers
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Why blockchain new node verify all transactions in blocks?

Hello I'm the student studying blockchain and bitcoin. I have a question that why all node verify all transactions in blocks. I check if new node connect bitcoin network, then the all transactions in ...
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How does Blockchain Exploler or wallet sync with node

So I'm building blockchain implementation and I cant get my head around how will blk explorer see block height of 1 I made a simple indexer and blk explorer, and when it gets a new block via RPC it ...
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2answers
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How/When is mining reward given in the presence of forking / orphan chain?

I am aware this is related to this question. However, I am specifically curious about what would happen to the mining rewards, not the transactions, under a forking condition. As shown in the picture....
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How can I build an iOS wallet app for altcoin? [closed]

How can I build an iOS wallet app for altcoin which is a clone of bitcoin? I can build a wallet for windows android linux macos, but I can't find one for iOS.
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I want to pre-hardcode my fallbackfee settings

I want to pre-hardcode my fallbackfee settings so that they are uniform across all wallet nodes. In which file should I put it, and not in bitcoin.conf?
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2answers
62 views

Bitcoin could work in principle with pen and paper and carrier pigeons. Could it?

Bitcoin could work in principle with pen and paper and carrier pigeons bringing the result of computations-by-hand back and forth to a public square: the ledger would work, but its intended use case ...
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3answers
63 views

bitcoin private key usage

My next question is how Private Key needed to spend coins. According to my understanding for transaction needed below steps: A wants to send 10 coin to B A make transaction example: from: A, to :B ...
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1answer
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I've built a bitcoin miner and mined. Now what I do?

I've mined bitcoin to test and understand cryptocurrency better. Which generated this hash 00000431fb66ed96815b3829e975c2235a64b9a646c0bd1cc526dc1727c1f16b(nonce value of 300712) What I do with this ...
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Solana blockchain. How can i generate private key? [closed]

const solanaWeb3 = require("@solana/web3.js"); const solanatoken = require("@solana/spl-token"); var wallet = solanaWeb3.Keypair.generate(); console.log("public key...&...
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create altcoin connect nodes send [closed]

I am cloning bitcoin to create an original coin. I have prepared a total of two Ubuntu systems, one local and one on AWS. I want to set up nodes with these and connect them to each other, but it doesn'...
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1answer
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When transactions of orphan block go back to the mempool?

Imagine there are two collision blocks A and B. These are mined at the same time. One miner created new block C on top of block A and longest chain happened. Do transactions of block B go back to ...
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Overflow bug bad chain length [duplicate]

Can someone recall how many blocks have been mined on the overflow bug chain until the new chain with the patch became the longer one?
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1answer
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what is the difference in bitcoin core between ? getblocktemplate or generatetoaddress?

what is the difference between: bitcoin-cli getblocktemplate '{"rules": ["segwit"]}' and bitcoin-cli generatetoaddress 11 "myaddress" as i understand it its both for ...
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Where is my money, do i have access to it?

On 10/06/21 I tried to pay for an order with bitcoin. BCH. It went from bitcoin to blockchair to simpleledger:pzt39mmtjfs8trthwvvpq0v7ktjc4wyvyqtdpmf2eh, Transaction hash ...
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How can I calculate the correct fees for a blockchain transaction?

How can I calculate the correct fees for a blockchain transaction? I use https://bitcoinfees.earn.com/api/v1/fees/recommended. But when creating a transaction with any of these commissions, I get an ...
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1answer
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When one miner created a new block and won the mining race, what other miner do next?

Imagine that wee have 10 indexed blockchain. Now, I start mining for index 11 block referencing index10's hash, I mean, the last hash data. Also, other miners starts too. When other miner finishes ...
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1answer
78 views

If malicious person(node) tampered withone block transaction, what's gonna happen?

I understand that if one bad person(node) tampered one block of his/her blockchain, the block hash data changed completely different. Let's say each node has 10 indexed blockchain and index4 block has ...
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2answers
35 views

how do nodes agree or disagree after new block is create?

I'm new to blockchain field and I read one article. article In this article of Authorization chapter, it is said that "For a public blockchain, the decision to add a transaction to the chain is ...
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3answers
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Will the bitcoin blockchain eventually grow too large to be able to be run 'by anyone'?

A key component of bitcoin is its decentralization (which effectively only exists with BTC and virtually nothing else). Part of this decentralization is the decentralization of the bitcoin nodes, ...
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44 views

Who are Merawing.net [duplicate]

Hello I have been contacted by this company saying about your withdrawal process. As I told you at the moment your funds are in the Blockchain system. With the help of artificial intelligence, we have ...
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1answer
49 views

Why Is it not possible to truncate the blockchain after Corruption detected

After running bitcoind (as part of myNode) for 6 monhths with no issue, I got this error: Fatal LevelDB error: Corruption: checksum mismatch: /home/bitcoin/.bitcoin/indexes/txindex/257701.log At ...
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1answer
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How to find traitor in Byzantine General Problem

I am new to this problem and trying to understand it. For example if I have 7 generals, 4 of them are honest and 3 of them are traitors. Now, how do I know which 4 generals are honest generals because ...
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1answer
20 views

How can I -abort ./bitcoind -reindex-chainstate?

I made files re-accessible. Now we could return to a later, already synchronized state with the files. I tried to put ./bitcoind -reindex-chainstate=0, also in a bitcoin.conf, also directly calling ...
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1answer
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Why there are signature and public key pair on blocks when transaction verifying is over

I'm student studying about bitcoin and blockchain. I want to know why all blocks have signature and key pair after the transaction is over. Why I ask this, I'm studying post quantum cryptography (PQC) ...
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1answer
41 views

How is transaction on exchanges that trade bitcoins connected to blockchain?

According to this answer, since the transaction on exchanges are internal, the transaction on blockchain is irrelated to them. But is the transaction on exchanges that trade bitcoins really not ...
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25 views

What prevents another node from sending an existing transaction? [duplicate]

To my understanding, when someone wants to send a transaction they will broadcast a message to the nodes that they are connected. What stops someone from sending a transaction that was sent to them ...
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23 views

How to Retrieve My Bitcoin Cash Sent to a Bitcoin Wallet [duplicate]

I accidentally sent Bitcoin Cash from my Payeer account to a Merchants Bitcoin Wallet, The Marchant never received it, They don't have a Bitcoin cash account and Only a Bitcoin Wallet account. Am I ...
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Storage of the transaction chain [duplicate]

I was looking into the bitcoin developer documentation and going through the RPCs. I was wondering if the blockchain consisted of the list of transactions, then how is the transaction information ...
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1answer
41 views

Space of Bitcoin Blockchain [duplicate]

I am a beginner of Bitcoins. I read here that the size of the blockchain is heavy HUNDREDS of gigabytes. I also read that one of the reasons bitcoin is safe is that EVERY user keeps a local copy of ...
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25 views

Signing a Transaction with Master Node for Derived Account

I am trying to learn HD Wallets. For that purpose, I build something on Solana. I've created derived accounts and can sign transactions with their private/public keys. Here is my code: const ...
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1answer
39 views

Changing the blockchain requires more than just recalculating all hashes..?

New here! I read this everywhere - "To change some data in a blockchain, the malicious user will have to recalculate hash for every block starting from that particular block". My doubt is - ...
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273 views

Do Wallets need to be verified or activated? Crypto Support asking me to do that [duplicate]

1.5Bitcoins were stolen form me in 2019, and a company Merawing contacted me a few weeks again, saying that they work with Crypto Regulation of Cyprus and that they would help me getting my bitcoins ...
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1answer
38 views

Why is the rate of reindexing chainstate not constant?

What determines the speed of the reindexing-chainstate in the different times? I spend a few days (2 week) for reindexing locally on my new HDD, and I noticed one thing: the speed of reindexing is ...
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0answers
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Where can I download the bitcoin blockchain to do offline analysis?

Where can I download the bitcoin blockchain to do some offline analysis. edit: Ideally I'd like to download .txt (or another file extension, e.g. .dat, as long as the contents are unencoded and human ...
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1answer
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Crpyto Bitcoin Insurance

How will the Bitcoin Crypto market compete against theft, if other fiat currencies have similar to FDIC insurance? In this article, some thieves did a phone swap, got a two factor authentication code,...
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How to load Bitcoin-qt using blockchain directory already existing on a hard drive?

I've had issues with downloading the blockchain using windows/mac. For some reason, it would eventually cause an issue whilst downloading and cause me to have to start again. Instead, I have been ...
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1answer
40 views

Inactive nodes, validation & 51%; full & partial nodes; validation by miners vs wallets

Questions Suppose a node doesn't have internet connection then it would not receive the broadcast of other nodes then does the blockchain propagates without the validation of that node ( that is, is ...
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1answer
512 views

Why discrepancies in blockchain GB size between Mac and web sources?

On a Mac which Bitcoin Core updated a few minutes ago, the the Blocks folder contains 409.55 GB and the Chainstate folder contains 4.57 GB. But... https://www.blockchain.com/charts/blocks-size shows, ...
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1answer
33 views

How can I get RawTX transactions?

I used to be able to get RawTX transactions on the Blockchain using the link: https://blockchain.info/tx/60183ab915f2f4b0190605f98bd0e9f8eafe13a1c902b3ae87ecd0dfc8a599a0?format=hex But the site ...
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3answers
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Do I have a chance to commit a transaction without any network fee?

I know how transaction fees are calculated. Also I understand that a transaction with a higher fee will be approved much faster than a transaction with the lowest one. Does the bitcoin protocol allow ...
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1answer
32 views

How many blocks extra does one need before it's competitor is deemed stale?

so when two equally valid blocks are discovered at roughly the same time, a conflict occurs, nodes should wait for the strongest fork of the chain to emerge and develop before placing trust in the ...
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1answer
48 views

How do I use Bitcoin Core (fully synced) to "backtrack" a receive address?

I'm trying to "reverse-track" my current Bitcoin wallet to see its exact history on the blockchain, backwards. I have a fully synced Bitcoin Core installed. What command do I use in its ...
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1answer
57 views

Why .bitcoin is at /root in Arch/Manjaro Linux?

I've installed bitcoin-core and downloaded the blockchain in Ubuntu. Now that I have switched to Manjaro Linux and installed bitcoin-core again, It creates the .bitcoin directory in /root/.bitcoin/ ...
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How to merge the datadir with .bitcoin directory?

I changed the path of datadir in bitcoin.conf from .bitcoin directory to somewhere else. Now that I need to backup my blockchain data, I want to have both .bitcoin and blockchain data together. ...
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40 views

how to do sha256(sha256(modified transaction)) and find z1 and z2 value

hi I tried to get z1 and z2 value but I cant understand. can any one help me with example for finding z1 and z2. or alternate website for 2coin.org example: see this trans. Two identical R value ...
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2answers
102 views

How bitcoin exactly works?

Everyone says, Bitcoin is decentralized. No central server is "hosted the app" But no matter how hard i am trying to get a grasp of it, i still couldn't understand how it works for exactly ...
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35 views

My bitcoin was approved but not spent [duplicate]

So i found out that my transaction was deemed suspicions for money laundering I guess. lol... of course it wasn't. I opened an account with bitcoin exchange and when i went to blockchain.com to send ...
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0answers
30 views

Power outage during Bitcoin Core initial synchronization

I had a power outage when I was half way through my Bitcoin Core initial synchronization. Is there a way to pick up where it left off or do I need to start over?
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1answer
93 views

Already mined block hash showing zeros at the end when I hash it in online sha256 two times

Hi I tried hashing a already mined block with this block header ...

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